Weight sorter

ABSTRACT

The invention provides a weight selecting apparatus capable of automatically performing calibration, and provides a weight selecting apparatus capable of certainly carrying objects to be inspected with a relatively simple mechanism and performing weight measurement of the objects. The objects, after being subjected to weight measurement by a first weighing unit  2 , are sampled by a sampler  5,  and those of the objects thus sampled are subjected to weight measurement by a second weighing unit  6 . A calibration unit compares, for the same object, the measured result with that obtained by the first weighing unit  2  and discriminates whether or not a difference therebetween is within a specific error range, to perform calibration of the first weighing unit  2 . Further, as a carrier  3  for carrying the objects to the weighing unit  2  one by one, there is used an intermittently rotatable carrying roller  32  having in its outer peripheral surface portion a plurality of carrying pockets  321.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/JP98/03078 which has an Internationalfiling date of Jul. 9, 1998, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a weight selecting apparatus forautomatically measuring weights of products and other articles in thevarious industrial fields of medicines, chemicals, foods and the like;inspecting whether or not the weight of each of the objects to beinspected is within a specific weight range; and selecting the objectsinto non-defective ones and defective ones. In particular, the presentinvention relates to a weight selecting apparatus capable ofautomatically performing, at specific intervals, a calibrating operationof inspecting the accuracy of a weighing unit for performing weightmeasurement thereby certainly performing inspection at a highreliability, and also relates to a weight selecting apparatus forcertainly carrying objects to be inspected with a relatively simplemechanism and performing weight measurement of the objects.

BACKGROUND ART

In the various industrial fields, as one of quality control items, ithas been performed to measure weights of products and other articles;inspect whether or not the weight of each of the objects to be inspectedis within a specific range; and select the objects into non-defectiveones and defective ones. In the field of medicines, particularly, weightinspection has been regarded as one of extremely important inspectionitems. This is because a variation in weight directly leads to avariation in effective content and such a variation in effective contentpresents a large problem particularly for a medicament with its doesrequired to be strictly managed.

Recently, weights of medicines such as capsules have come to beautomatically inspected using a weight selecting apparatus, and as sucha weight selecting apparatus there has been known an apparatus shown inFIG. 9.

The weight selecting apparatus shown in FIG. 9, adapted for weightinspection of capsules, includes a hopper “a” for continuously feedingcapsules as objects to be inspected; a magazine “b” for feeding thecapsules from the hopper “a” to a weighing base “g” one by one; aweighing unit “c” for measuring weights of the capsules; anacceptability determining unit (not shown) for determining theacceptability of each capsule on the basis of the measured result; and aselecting/recovering unit “d” for selecting the capsules intonon-defective ones and defective ones on the basis of the acceptabilitydetermination and recovering them.

The hopper “a” is formed into an approximately funnel shape in which aspecific number of capsules are to be stored. As the amount of capsulesstored in the hopper “a” is reduced, new capsules are supplied from alarge hopper “e” shown in FIG. 9, whereby a specific number of capsulesare usually stored in the hopper “a”.

The magazine “b” is a vertically movable pipe with its upper endinserted through the hopper “a”, and a shutter “f” for opening/closing alower end opening portion of the magazine “b” is mounted to the lowerend portion of the magazine “b”. The weighing unit “c” includes a V-rail“h”, having a V-shaped cross section, for guiding each capsule suppliedfrom the magazine “b” to a weighing base “g”; a pusher “i” for turningsideways each capsule supplied on the V-rail “h” and pushing the capsuleout of the V-rail “h” to move it on the weighing base “g”; a stopper “n”for stopping each capsule moved onto the weighing base “g” at a specificposition; and an injector “p” for moving each capsule from the weighingbase “g” to the selecting/recovering unit. The selecting/recovering unit“d” includes an ejecting chute “j” for ejecting each capsule afterweight measurement; a defective ejecting chute “k” branched from theejecting chute “j”; and a selecting gate “m” provided at a branch pointwhere the defective ejecting chute “k” is branched from the ejectingchute “J”.

The weight inspection using the above weight selecting apparatus isperformed as follows:

That is to say, the capsules in the hopper “a” are charged in themagazine “b” in a state being aligned in a row by vertical motion of themagazine “b”, and as shown by a broken line in FIG. 9, the shutter “f”is temporarily opened when the magazine “b” reaches the lowermost pointand thereby one of the capsules is discharged from the lower end openingportion of the magazine and is placed on the V-rail “h”. The pusher “i”is immediately moved in the horizontal direction to turn sideways thecapsule on the V-rail “h” and move it on the weighing base “g”. Themoving capsule is stopped by the stopper “n” at a specific position onthe weighing base “g”, followed by weight measurement. After weightmeasurement, as shown by a broken line in FIG. 9, the stopper “n” ismoved downward to open a charging port of the ejection chute “j” and atthe same time the injector “p” is moved as shown by an arrow in FIG. 9to charge the capsule on the weighing base “g” into the ejection chute“j” of the selecting/recovering unit “d”. At this time, the acceptancedetermining unit (not shown) determines, on the basis of the result ofweight measurement, whether or not the weight of the capsule is within aspecific range, and opens/closes the selecting gate on the basis of thedetermined result. In the case where the capsule is determined as anon-defective capsule having a weight being in the specific range, theselecting gate “m” closes the port of the defective ejecting chute “k”,whereby the non-defective capsule is ejected outside the apparatusthrough the ejecting chute “j”. On the other hand, in the case where thecapsule is determined as a defective capsule having a weight being outof the specific range, as shown by a dotted line in the figure, theselecting gate “m” is opened and thereby the upper end opening portionof the defective ejecting chute “k” is opened and also the selectinggate “m” blocks the ejecting chute “j” at the branch point between thedefective capsule ejecting chute “k” and the same to introduce thedefective capsule into the defective ejecting chute “k”. Thus, thedefective capsule is selected and recovered through the defectiveejecting chute “k”. Thereafter, the above operation is continuouslyrepeated, to thus automatically select the weights of the capsules.

The related art weight selecting apparatus, however, has a disadvantagethat a so-called calibration for inspecting and confirming the accuracyof weight measurement by the weighing unit “c” must be manuallyperformed each time, and thereby the calibration work is madeburdensome.

To be more specific, the “calibration” is to compare a measuringinstrument with a standard (reference) instrument or a standard sample,confirm that an error therebetween is within a reference value, and toadjust and repair the measuring instrument if the error is out of thereference value; and to stably obtain products each having a specificquality, each measuring instrument must be subjected to calibration at anecessary period determined according to the purpose and importance.

In the above-described related art weight selecting apparatus, thecalibration is performed by confirming the accuracy of a balance of theweighing unit “c” using a reference weight, and adjusting and repairingthe balance if an error measured is more than a reference value.However, since such an apparatus is generally configured such that anumber of inspection lines composed of measurement mechanisms shown inFIG. 9 are arranged in a plurality of rows (6 rows and 12 rows types,commercially available apparatus) for processing a large amount ofcapsules for a short time, the calibration must be performed using thereference weight for each line, so that the calibration work takes alarge labor. As a result, it is expected to develop a weight selectingapparatus capable of automatically performing the above calibration.

The above-described related art weight selecting apparatus also has adisadvantage that since capsules are carried from the hopper “a” to theweighing base “g” one by one, followed by weight measurement, and thecapsules are fed to the selecting/recovering unit “d”, the carryingmechanism is complicated.

That is to say, as described above, the related art weight selectingapparatus is configured such that one capsule is discharged from thelower end of the magazine “b” and is placed on the V-rail “h” when thevertically movable magazine “b” reaches the lowermost point, and thecapsule is turned sideways by the pusher “i” and at the same time it ismoved to the weighing base “g” for weight measurement; and directlyafter weight measurement, the stopper “n” is moved to open the chargingport of the ejecting chute “j” and also the capsule on the weighing base“g” is charged into the ejecting chute “g” by the injector “p”. That isto say, the carrying mechanism for carrying the capsule has a number ofmoving parts such as the magazine “b”, pusher “i”, stopper “n”, injector“p”, and the like, and a drive mechanism and a control mechanism formoving these parts at correct timings are required to be provided. Inthis way, the related art weight selecting mechanism has a verycomplicated mechanism for carrying capsules, which obstructs theimprovement of processing ability and raises the parts cost, assemblingcost and the like, and further may cause a failure in the carrying stepsuch as breakage of capsules during carrying them.

In view of the foregoing, the present invention has been made, and afirst object of the present invention is to provide a weight selectingapparatus capable of automatically performing calibration, that is,eliminating the necessity of performing the burdensome calibratingoperation by manual work, thereby effectively performing high accurate,high reliable weight measurement.

A second object of the present invention is to provide a weightselecting apparatus capable of certainly carrying objects to beinspected with a relatively simple mechanism, measuring weights of theobjects, and certainly ejecting the objects after weight measurement.

DISCLOSURE OF INVENTION

To achieve the first object, according to a first invention, there isprovided a weight selecting apparatus including: a feed unit forcontinuously feeding objects to be inspected; a first weighing unit formeasuring weights of the objects; a carrying means for carrying theobjects fed from the feed unit to the first weighing unit one by one; anacceptability determining unit for comparing the result of weightmeasurement by the first weighing unit with a specific reference valueto determine the acceptability of each of the objects; a selecting meansfor selecting the objects into non-defective ones each having a weightbeing within a specific weight range and defective ones each having aweight being out of the specific weight range on the basis of thedetermined results by the acceptability determining unit; a samplingmeans for performing sampling for the objects having been subjected toweight measurement by the first weighing unit; a second weighing unitfor calibration, which is adapted to measure weights of those of theobjects sampled by the sampling means; and a calibration unit forcomparing, for the same object, the result of weight measurement by thefirst weighing unit with the result of weight measurement by the secondweighing unit and determining whether or not a difference therebetweenis within a specific error range; wherein in a usual state, the objectscontinuously fed from the feed unit are carried to the first weighingunit one by one by the carrying means and are subjected to weightmeasurement by the first weighing unit, being subjected to acceptabilitydetermination on the basis of the measured results by the acceptabilitydetermining unit, and are selected into non-defective ones and defectiveones on the basis of the determined results by the selecting means andare recovered; and at specific intervals, the objects having beensubjected to weight measurement by the first weighing unit are subjectedto sampling by the sampling means; those of the objects thus sampled aresubjected to weight measurement by the second weighing unit; and for thesame object, the measured result is compared with that obtained by thefirst weighing unit by means of the calibration unit, to performcalibration of the first weighing unit.

That is to say, in the weight selecting apparatus of the presentinvention, the objects having been subjected to weight measurement bythe first weighing unit are subjected to sampling by the sampling means,and those of the objects thus sampled are subjected to weightmeasurement by the second weighing unit. Then, the calibration unitcompares, for the same object, the measured result with that obtained bythe first weighing unit and discriminates whether or not a differencetherebetween is within a specific error range, to thus performcalibration of the first weighing unit by making use of the objects tobe inspected without use of a reference weight.

Accordingly, it is possible to automatically perform calibration bystarting the sampling means, second weighing unit, and calibration unitat specific intervals arbitrarily set.

In the weight selecting apparatus of the present invention, while notexclusively, the above selecting means may include an ejecting chute forejecting the objects having been subjected to weight measurement by thefirst weighing unit; a defective ejecting chute, branched from theejecting chute, for introducing the objects to reversely rotatablenon-defective recovering/carrying device; and a non-defective/defectiveselecting shutter, provided at the branch point where the defectiveejecting chute is branched from the ejecting chute, for opening/closinga port of the defective ejecting chute; wherein the defective ejectingchute, non-defective/defective selecting shutter, and defectiverecovering/carrying device of the selecting means are used as thesampling means upon calibration.

That is to say, in a usual state, the non-defective/defective selectingshutter is opened/closed on the basis of the determined results obtainedby the acceptability determining unit, and the non-defective objects areejected through the ejecting chute to be recovered and the defectiveobjects are introduced to the defective recovering/carrying devicethrough the defective ejecting chute which is branched from the ejectingchute by opening the non-defective/defective selecting shutter and arerecovered, to thereby select the objects into nondefective ones anddefective ones and recover them. On the other hand, upon calibration,the non-defective/defective selecting shutter is unconditionally openedto introduce the objects having being subjected to weight measurement bythe first weighing unit to the defective recovering/carrying devicethrough the defective ejecting chute, and the defectiverecovering/carrying device is reversely rotated to carry the objects toin the direction different from the carrying direction upon usualdefective recovery, that is, to feed the objects to the second weighingunit, whereby the objects are subjected to sampling for calibration.

Since the sample means is configured using the selecting means asdescribed above, it is possible to certainly perform sampling forcalibration with a relatively simple mechanism without provision of anycomplicated path, and hence to miniaturize the apparatus and reduce theparts cost. Further, since the usual weight measurement or inspectioncannot be naturally performed until the accuracy of the first weighingunit is confirmed, the inspection efficiency is not reduced even byperforming sampling for calibration by making use of the selectingmeans.

In the case where the selecting means is comprised of the ejectingchute, defective ejecting chute, and non-defective/defective selectingshutter, preferably, a defective ejection sensor for detecting passingof the objects is mounted on the defective ejecting chute or in thevicinity of an ejection port thereof, and a reversely rotatablenon-defective recovering/carrying device for recovering non-defectiveones of the objects is disposed ahead of the ejecting chute, whereinejection of the object determined as a defective one by theacceptability determining unit is detected by the defective ejectionsensor, and in the case where the defective object is not detected, thenon-defective recovering/carrying device is reversely rotated to prevententrainment of the defective object in the non-defective objects. Thismakes it possible to certainly prevent entrainment of a defective objectinto non-defective objects, and hence to perform weight inspection witha high reliability.

As described above, according to the weight selecting apparatus of thepresent invention, it is possible to automatically perform calibration,that is, eliminate the necessity of performing burdensome calibratingoperation by manual works, and hence to reduce a labor required formonitoring or calibrating work by an operator and also effectivelyperform high accurate, high reliable weight inspection.

To achieve the above second object, according to a second invention,there is provided a weight selecting apparatus including: a feed unitfor continuously feeding objects to be inspected; a weighing unit formeasuring weights of the objects; a carrying means for carrying theobjects fed from the feed unit to the weighing unit one by one; anacceptability determining unit for comparing the result of weightmeasurement by the weighing unit with a specific reference value todetermine the acceptability of each of the objects; and a selectingmeans for selecting the objects into non-defective ones each having aweight being within a specific weight range and defective ones eachhaving a weight being out of the specific weight range on the basis ofthe determined results by the acceptability determining unit; whereinthe objects continuously fed from the feed unit are carried to theweighing unit one by one by means of the carrying means and subjected toweight measurement by the weighing unit, being subjected toacceptability determination on the measured results by the acceptabilitydetermining unit, and are selected into non-defective ones and defectiveones on the basis of the determined results by the selecting means andare recovered; characterized in that the carrying means includes atleast one intermittently rotatable carrying roller having in its outerperipheral surface portion a plurality of carrying pockets forcontaining the objects, wherein the objects are contained in thecarrying pockets on a one-to-one basis and carried by intermittentrotation of the carrying roller; each of the objects is placed on aweighing base of the weighing unit at the lowermost point of thecarrying roller in a state being contained in the corresponding one ofthe carrying pockets, being subjected to weight measurement in a periodin which the carrying roller is left as intermittently stopped, and ismoved from the weighing base by intermittent rotation of the carryingroller; and the object thus measured in weight is ejected from thecarrying pocket and is transferred to the selecting means.

That is to say, the above weight selecting apparatus is configured suchthat as the carrying means for carrying objects to be inspected to theweighing unit one by one, there is used at least one carrying rollerhaving a plurality of carrying pockets for containing the objects,wherein the objects fed from the feed unit are carried to the weighingbase of the weighing unit by intermittent rotation of the carryingroller, being subjected to weight measurement, and are fed to theselecting means by intermittent rotation of the carrying roller.Accordingly, by provision of at least one carrying roller, objects to beinspected can be carried sequentially from the feed unit to the weighingbase and to the selecting means, so that the carrying unit capable ofcertainly carrying the objects can be constituted of a reduced number ofparts. Since the carrying unit may have at least one carrying roller asa simply movable part, that is, intermittently rotated part, it ispossible to eliminate the necessity of provision of a complicated drivemechanism or control mechanism.

Consequently, according to the weight selecting apparatus of the presentinvention, as compared with the above-described related art weightselecting apparatus in which objects to be inspected are carried bycontrolling a number of movable parts requiring complicated motions withtimings adjusted accurately, it is possible to accurately, certainlycarry objects to be inspected by a simple mechanism with a reducednumber of parts, and hence to improve the processing ability and reducethe cost.

In addition, the carrying means of the weight selecting apparatus usesthe intermittently rotated carrying roller as a member for placingobjects to be inspected on the weighing base one by one and moving themto the selecting means after weight measurement, and depending on thekind/feature of the objects and the specification of the feed unit forfeeding the objects, the carrying means may be comprised of acombination of the carrying roller and another member. For example, likea first embodiment to be described later, the carrying unit can becomprised of a combination of the carrying roller and a feed drum forcertainly charging the objects continuously fed from the feed unit intocarrying pockets formed in the carrying roller, or like a secondembodiment to be described later, it can be comprised of a combinationof the carrying roller and a vibration feeder for sequentially feedingthe objects into the carrying pockets of the carrying roller byvibration.

The carrying means using the intermittently rotated carrying roller is,of course, suitably used as the carrying means of the above-describedweight selecting apparatus having the calibration function, whereby itis possible to improve the processing ability of the weight selectingapparatus having the calibration function and also to reduce thematerial cost and manufacturing cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view showing the schematic configuration of a weightselecting apparatus according to a first embodiment of the presentinvention;

FIG. 2 is a side view showing the schematic configuration of the weightselecting apparatus shown in FIG. 1;

FIG. 3 is a sectional view, partly on an enlarged scale, showing a firstweighing unit of the weight selecting apparatus shown in FIG. 1 and itsneighborhood;

FIG. 4 is a sectional view, partly on an enlarged scale, illustratingthe operation of the weight selecting apparatus for transferringcapsules (objects to be inspected) from a pan (weighing base) of thefirst weighing unit to an ejecting chute of a selecting means;

FIG. 5 is a sectional view, partly on an enlarged scale, showing acarrying roller and a posture changing plate of the weight selectingapparatus;

FIG. 6 is a sectional view, partly on an enlarged scale, showing adefective recovering conveyor of the weight selecting apparatus;

FIG. 7 is a front view of the schematic configuration of a weightselecting apparatus according to a second embodiment of the presentinvention;

FIG. 8 is a sectional view, partly on an enlarged view, showing avibration feeder for feeding capsules to a carrying roller of the weightselecting apparatus shown in FIG. 7; and

FIG. 9 is a schematic view showing a related art weight selectingapparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail.

[Embodiment 1]

FIGS. 1 to 6 show a weight selecting apparatus according to a firstembodiment of the present invention, for measuring weights of capsules,discriminating whether or not the weight of each capsule is within aspecific weight range, automatically selecting the capsules intonon-defective ones each being within the specific weight range anddefective ones each being out of the specific weight range, andrecovering them.

The weight selecting apparatus includes, as shown in FIGS. 1 and 2, ahopper 1 (feed unit) for storing a specific number of capsules andcontinuously feeding the capsules; a first weighing unit 2 for measuringweights of the capsules; a carrying means 3 for carrying the capsulessupplied from the hopper 1 at random to the first weighing unit 2 one byone; an acceptability determining unit (not shown) for determining theacceptability of each capsule on the basis of the measured resultobtained by the first weighing unit 2; a selecting means 4 for selectingthe capsules into non-defective ones and defective ones on the basis ofthe determined results by the acceptability determining unit; a samplingmeans 5 for performing, upon calibration, sampling for the capsulesafter weight measurement; a second weighing unit 6 for measuring weightsof those of the capsules sampled by the sampling means 5; and acalibration unit (not shown) for comparing, for each capsule sampled,the result of weight measurement by the first weighing unit 2 with theresult of weight measurement by the second weighing unit 6, therebyperforming calibration of the first weighing unit 2 on the comparisonresult.

The carrying unit 3 includes, as shown in FIGS. 1 and 2, a feed drum 31rotatable with its outer peripheral surface being partially close to thehopper 1; and a carrying roller 32 rotatably disposed under the feeddrum 31 with its outer peripheral surface being close to the outerperipheral surface of the feed drum 31.

As shown in FIGS. 2 and 3, a number of feed pockets 311 for containingthe capsules in upright postures (the wording “upright posture” means aposture of the capsule with its axis directed in the radial direction ofthe drum) are formed in the outer peripheral surface portion of the feeddrum 31 in such a manner as to be aligned in a row along the peripheraldirection of the drum 31, and a plurality of rows (12 rows in thefigure) of the pockets 311 are formed in the outer peripheral surfaceportion of the drum 31. As shown in FIG. 3, the feed drum 31 has suctionshoes 312 provided in the feed pockets 311 in such a manner as to becommunicated to the feed pockets 311 in a one-to-one relationship. Wheneach capsule is received from the hopper 1 into the feed pocket 311, thefeed pocket 311 is sucked through the corresponding suction shoe 312,whereby the capsule can be smoothly transferred from the hopper 1 intothe feed pocket 311. Further, as shown in FIGS. 1 and 3, the one-fourthperipheral portion of the feed drum 31 extending in the rotationaldirection from the upstream side to the vicinity of the lowermost pointis covered with a cover plate 313 for preventing slip-off of thecapsules.

On the other hand, as shown in FIGS. 2 to 4, a number of carryingpockets 321 are formed in the outer peripheral surface portion of thecarrying roller 32 in such a manner as to be aligned in a row along theperipheral direction correspondingly to the feed pockets 311 of the feeddrum 31, and a plurality of rows (12 rows in the figures) of thecarrying pockets 321 are formed correspondingly to the plurality of rowsof the feed pockets 311. The carrying pocket 321 is adapted to containthe capsule in a lateral turning state (the wording “lateral turningstate” means a state of the capsule with its axis directed in the axildirection of the roller). In this case, as shown in FIGS. 3 and 4, theleading end of the capsule contained in the carrying pocket 321 in theupright posture projects from the outer peripheral surface of thecarrying roller 32. Further, as shown in FIGS. 1, 3 and 5, the aboutone-fourth outer peripheral portion of the carrying roller 32 in therotational direction from the upstream side to the vicinity of thelowermost point is covered with a posture changing plate 322. As shownin FIG. 5, the upper end portion of the posture changing plate 322 hasV-grooves 323 corresponding to the rows of the carrying pockets 321.

The feed drum 31 and the carrying roller 32 are driven by a drive source12 such as a motor (see FIG. 2) while being controlled by an indexdevice 13 (see FIG. 2) for indexing the rotating speed and angle of eachof the feed drum 31 and the carrying roller 32 in such a manner as to beintermittently rotated in synchronization with each other in thereversed direction (the feed roller 31 is rotated counterclockwise andthe carrying roller 32 is rotated clockwise in FIG. 1). Although thefeed drum 31 and the carrying roller 32 are intermittently rotated bycontrol of the index device 13 in this embodiment, they may beintermittently rotated by a step motor (not shown) in place of the indexdevice 13.

Next, as shown in FIGS. 1 to 3, the first weighing unit 2 includes adifferential transformer type balance 21 having a pan (weighing base) 24positioned close to the lowermost point of the peripheral surface of thecarrying roller 32. The weight of each capsule carried by the carryingroller 32 is measured by the differential transformer type balance 21.In this case, as shown in FIG. 2, the differential transformer balances21 are arranged in a one-to-one relationship with the rows of thecarrying pockets 321 of the carrying roller 32. In the example shown inFIG. 2, 12 pieces of the differential transformer balances 21 arearranged correspondingly to 12 rows of the carrying pockets 321. In FIG.3, reference numeral 22 indicates a differential transformer, and 23 isan amplifier for the differential transformer. While not particularlyshown, the upper surface of the pan 24 of the differential transformertype balance 21 is formed such that the central portion is recessed inan approximately V-shape allowing a capsule to be placed on the recessand to be stably subjected to weight measurement.

The result of weight measurement by each differential transformer typebalance 21 of the first weighing unit 2 is supplied to the acceptabilitydetermining unit (not shown), and the acceptabilities of the weights ofthe capsules are determined for each differential transformer typebalance 21, that is, for each pocket row. The determination by theacceptability determining unit is performed by comparing the result ofweight measurement by each differential transformer balance 21 with apreset specific reference value and discriminating whether or not adifference therebetween is within a specific allowable range. If thedifference is within the allowable range, the capsule is determined as anon-defective one, and if the difference is more than the allowablerange, it is determined as a defective one.

The selecting means 4 includes, as shown in FIG. 1, a square pipe-likeejecting chute 41, a square pipe-like defective ejecting chute 42, and anon-defective/defective selecting shutter 43. The ejecting chute 41 istilted in a state in which the upper end opening portion is close to theouter peripheral surface of the roller 32 and is adjacent to thedifferential transformer type balance 21 in the vicinity of thelowermost point of the carrying roller 32. The defective ejecting chute42 is branched from an intermediate portion of the ejecting chute 41 andextending downward. The non-defective/defective selecting shutter 43 isprovided at a branch point where the defective ejecting chute 42 isbranched from the ejecting chute 41 and is adapted to open/close theupper end opening portion of the defective ejecting chute 42.

The ejecting chutes 41 are arranged in a one-to-one relationship withthe rows of the carrying pockets 321 of the carrying roller 32. Whilenot clearly shown, 12 pieces of the ejecting chutes 41 are arrangedcorrespondingly to 12 rows of the carrying pockets 321. The defectiveejecting chute 42 and the non-defective/defective selecting shutter 43are mounted to each ejecting chute 41. As shown in FIGS. 1 and 3, eachnon-defective/defective selecting shutter 43 is usually kept in a stateof blocking the upper end opening portion of the defective ejectingchute 42, and when the defective determination is performed by theacceptability determining unit (not shown), as shown by a two-dot chainline in FIG. 3, the non-defective/defective selecting shutter 43 isopened to open the upper end opening portion of the defective ejectingchute 42 and block the ejecting chute 41, whereby the capsules flowingthrough the ejecting chute 41 are dropped in the defective ejectingchute 42.

As shown in FIGS. 1 and 2, a non-defective recovering conveyor 44 as areversely rotatable non-defective recovering/carrying device is disposedahead of the ejecting chute 41. A non-defective capsule ejected throughthe ejecting chute 41 is carried by the non-defective recoveringconveyor 44, and is recovered through a non-defective recovering chute441 (see FIG. 2). A defective recovering conveyor 45 as a reverselyrotatable defective recovering/carrying device is disposed ahead of thedefective ejecting chute 42, so that a defective capsule ejected throughthe defective ejecting chute 42 is carried by the defective recoveringconveyor 45 and is recovered in a defective recovering vessel 452 (seeFIG. 2) through a defective recovering chute 451 (see FIG. 2). In thiscase, a defective ejection sensor 453 (see FIG. 1) composed of a pair oflight emitting and receiving devices are arranged in the vicinity of thelower end opening portion of each defective ejecting chute 42. Thedefective ejection sensor 453 detects passing of the capsule, to therebyconfirm whether or not the capsule determined as the defective one bythe acceptability determining unit (not shown) is ejected through thedefective ejecting chute 42.

To carry capsules to the non-defective recovering chute 441 anddefective recovering chute 451, as described above, the non-defectiverecovering conveyor (non-defective recovering/carrying device) 44 isusually rotated in the direction A in FIG. 2 and the defectiverecovering conveyor (defective recovering/carrying device) 45 is usuallyrotated in the direction B in FIG. 2; however, each of the non-defectiverecovering conveyor 44 and defective recovering conveyor 45 can bereversely rotated. According to the circumstances, the non-defectiverecovering conveyor 44 is reversely rotated in the direction C in FIG.2, and the defective recovering conveyor 45 is reversely rotated in thedirection D in FIG. 2.

To be more specific, in the case where the defective ejection sensor 453(see FIG. 1) does not confirm ejection of any defective capsule, thenon-defective recovering conveyor 44 is reversely rotated in thedirection shown by an arrow C in FIG. 2 to recover all of the capsuleson the non-defective recovering conveyor 44 in a temporarily storingvessel 443 through a temporarily storing chute 442. Meanwhile, incalibration of each differential transformer type balance 21 of thefirst weighing unit 2, the defective recovering conveyor 45 is reverselyrotated in the direction shown by an arrow D in FIG. 2 on the basis of acommand supplied from the calibration unit (not shown) to drop all ofthe capsules on the defective recovering conveyor 45 in the secondweighing unit 6 through a sampling chute 454.

Here, the defective ejecting chute 42, non-defective/defective selectingshutter 43, and defective recovering conveyor 45, which constitute mainparts of the above selecting means 4, also constitute main parts of theabove sampling means 5. For calibration, capsules for calibration aresampled by the sampling means 5 including these defective ejecting chute42, non-defective/defective selecting shutter 43, and defectiverecovering conveyor 45.

That is to say, upon calibration, on the basis of a command suppliedfrom the calibration unit (not shown), the non-defective/defectiveselecting shutter 43 is unconditionally opened irrespective of thedetermined result by the acceptability determining unit (not shown) orwithout acceptability determination to introduce all of the capsulesfrom the ejecting chute 41 onto the defective recovering conveyor 45through the defective ejecting chute 42, and the defective recoveringconveyor 45 is reversely rotated in the direction, shown by an arrow Din FIG. 2, reversed to the normally rotational direction upon recoveryof defective capsules, to feed the capsules to the second weighing unit6 through the sampling chute 454 for sampling capsules for calibration.

In this case, as shown in FIG. 6, the defective recovering conveyor 45includes a conveyor belt 455; a number of partitioning walls 456 erectedon the carrying plane of the conveyor belt 455 in such a manner as to bespaced from each other with equal intervals; and capsule holdingportions 457 formed between adjacent ones of the partitioning walls 456.Capsules having been fed from each defective ejecting chute 42 arecontained and held in the capsule holding portions 457 on a one-by-onebasis to be thus carried. The defective recovering conveyor 45 isintermittently rotated in the direction D in FIG. 2 upon calibration,whereby capsules contained and held in the capsule holding portions 457on the one-by-one basis are sequentially dropped on the second weighingunit 6 through the sampling chute 454 one by one and are measured inweight by the second weighing unit 6 one by one.

Here, as an instrument for weight measurement in the second weighingunit 6, there may be adopted any weight measuring instrument insofar asit is capable of automatically performing zero point adjustment andweight measurement with a high accuracy. While not exclusively, aMettler balance is suitably used, and it is also adopted in thisembodiment.

The calibration unit (not shown) starts the above-described samplingaction at arbitrary intervals previously set, and performs calibrationof each differential transformer type balance 21 on the basis of theresult of weight measurement by the second weighing unit 6. Thecalibrating operation by the calibration unit is performed by comparing,for the same capsule, the result of weight measurement by thedifferential transformer type balance 21 of the first weighing unit 2with the result of weight measurement by the second weighing unit 6, anddiscriminating whether or not a difference therebetween is within aspecific error range, thereby determining whether or not thedifferential transformer type balance 21 is required to be adjusted orrepaired.

Here, each of the acceptability determining unit (not shown) and thecalibration unit (not shown) may be comprised of a suitable computer. Inthis case, both the acceptability determining unit and the calibrationunit may be comprised of one computer. In addition, reference numeral 11in FIG. 1 indicates a brush roller for certainly loading capsules to beinspected from the hopper 1 into the feed pockets 311 of the feed drum31 on the one-to-one basis.

Next, there will be described the operation of the weight selectingapparatus in this embodiment upon weight Inspection of capsules and alsoupon calibration.

First, the operation of the weight selecting apparatus for weightInspection of capsules will be described. Capsules contained at randomIn the hopper 1 are transferred to and held In the feed pockets 311 ofthe feed drum 31 In upright postures, and are carried downward byintermittent rotation of the feed drum 31 in a state being contained andheld In the feed pockets 311 of the feed drum 31. In this case, at thestep of transfer of capsules from the hopper 1 into the feed pockets311, the delivery (or loading) of the capsules from the hopper 1 Intothe feed pockets 311 on the one-by-one basis Is smoothly performed bythe aid of suction of the interior of each feed pocket 311 through thecorresponding suction shoe 312 (see FIG. 3) and the brushing action dueto rotation of the brush roller 11. Further, each capsule carrieddownward by rotation of the feed drum 31 in the state being contained ineach feed pocket 311 certainly reaches the lowermost point of the feeddrum 31 while being prevented from being slipped off by the cover plate313 (see FIGS. 1 and 3). As shown in FIG. 3, at the lowermost point ofthe feed drum 31, each capsule is delivered, as kept in its uprightposture, from each feed pocket 311 to each carrying pocket 321 of thecarrying roller 32 rotated in synchronization with the feed drum 31.

Each capsule delivered into each carrying pocket 321 of the carryingroller 32 is, as shown in FIGS. 3 and 5, carried downward by rotation ofthe carrying roller 32 in the state being contained in the carryingpocket 321 in the upright posture. At this time, each capsule containedin each carrying pocket 321 in the upright posture is carried, with itsleading end projecting from the outer peripheral surface of the carryingroller 32, to a position at which the posture changing plate 322 isdisposed. Then, as shown in FIG. 5, the projecting end of each capsuleis pushed in the lateral direction by one inner edge of the V-shapedgroove 323 of the posture changing plate 322, so that each capsule isturned sideways to be contained in each carrying pocket 321 and iscertainly carried up to the lowermost point of the carrying roller 32while being prevented from being slipped off by the posture changingplate 322. As shown in FIG. 3, at the lowermost point of the carryingroller 32, the capsule in the carrying pocket 321 is placed on the pan24 of the differential transformer type balance 21 of the first weighingunit 2, and the weight of the capsule is measured by the differentialtransformer type balance 21 during a period when the intermittentlyrotated carrying roller 32 is kept as stopped.

The acceptability determining unit (not shown) compares the result ofweight measurement by the differential transformer type balance 21 witha preset specific reference value; discriminates whether or not adifference therebetween is within a specific allowable range, anddetermines the capsule as a non-defective one if the difference iswithin the allowable range and as a defective one if it is out of theallowable range. In the case where the measured value obtained either of12 pieces of the differential transformer type balances 21 is determinedto be defective, a defective detecting signal is immediately transmittedto a control unit (not shown) for controlling opening/closing of thenon-defective/defective selecting shutters 43, to open thenon-defective/defective selecting shutter 43 provided on the ejectingchute 41 concerned, thus leading to a state shown by a two-dot chainline in FIG. 3, that is, the upper end opening portion of the defectiveejecting chute 42 is opened and the ejecting chute 41 is blocked by theshutter 43.

Then, the carrying roller 32 is intermittently rotated again, so that asshown in FIG. 4, the capsule contained in the carrying pocket 321 ismoved from the pan 24 to a position over the upper end opening portionof the ejecting chute 41, and is slipped off from the carrying pocket321 by its dead weight and is dropped in the ejecting chute 41. Thecapsule determined as a non-defective one by the acceptabilitydetermining unit flows down in the ejecting chute 41 by its dead weight,and is placed on the non-defective recovering conveyor 44 and is carriedrightward in FIG. 2 by rotation of the non-defective recovering conveyor44 in the direction A in FIG. 2 to be thus ejected and recovered throughthe non-defective recovering chute 441.

On the other hand, the capsule determined as a defective one by theacceptability determining unit flows down by its dead weight in theejecting chute 41 being in a state in which the non-defective/defectiveselecting shutter 43 is opened, being dropped in the defective ejectingchute 42 branched from the ejecting chute 41, and is placed on thedefective recovering conveyor 45 through the defective ejecting chute42. The defective capsule placed on the defective recovering conveyor 45is carried leftward in FIG. 2 by rotation of the defective recoveringconveyor 45 in the direction B in FIG. 2, and is contained in thedefective recovering vessel 452 through the defective recovering chute451.

Upon ejection/recovering of the defective capsules, it is confirmedwhether or not the capsules determined as defective ones by theacceptability determining unit (not shown) are ejected through thedefective ejecting chute 42 by detecting passing of the capsules bymeans of the defective ejection sensor 453 (see FIG. 1), and in the casewhere the ejection of even one defective capsule is not confirmed, thenon-defective recovering conveyor 44 is reversely rotated in thedirection C in FIG. 2 to carry all of the capsules on the non-defectiverecovering conveyor 44 leftward in FIG. 2 and are recovered in thetemporarily storing vessel 443 through the temporarily storing chute442, in order to certainly prevent entrainment of any defective capsulein the non-defective capsules. In addition, the capsules recovered inthe temporarily storing vessel 443 may be returned into the hopper 1 tobe subjected to weight measurement again.

Thereafter, the same operation is continuously repeated to automaticallyselect capsules into non-defective ones and defective ones and recoverthem. In this case, in the weight selecting apparatus in thisembodiment, the differential transformer type balance 21 of the firstweighing unit 2 is automatically calibrated at intervals previouslyarbitrarily set in the calibration unit (not shown).

In the case where a calibration program in the apparatus in thisembodiment starts, weights of capsules are measured by the differentialtransformer type balance 21 and then the measured result is stored inthe calibration unit (not shown) and at the same time, thenon-defective/defective selecting shutter 43 is unconditionally openedirrespective of the determined result obtained by the acceptabilitydetermining unit or without acceptability determination. Accordingly thecapsules having been measured in weight by the differential transformertype balance 21 are all dropped on the defective recovering conveyor 45through the defective ejecting chute 42, and as shown in FIG. 6, thecapsules are contained in the capsule holding portions 457 of thedefective recovering conveyor 45 on a one-by-one basis. Then, thedefective recovering conveyor 45 is intermittently rotated in thedirection reversed to the rotational direction upon normal defectiverecovery, that is, in the direction D in FIG. 2, so that the capsulescontained and held in the capsule holding portions 457 on the one-by-onebasis are sequentially dropped, one by one, on the second weighing unit6 through the sampling chute 454 and are measured in weight, one by one,by means of the second weighing unit 6. In this case, the capsules aredropped on the pan of the Mettler balance of the second weighing unit 6one by one. In the apparatus shown in the figure, 12 pieces of thecapsules are finally placed on the pans of the Mettler balance for eachcalibration. The Mettler balance is configured such that zero pointadjustment is automatically performed directly after weight measurementof one capsule, and thereby it certainly performs weight measurement ofcapsules one by one. During such calibration, the weight selectingoperation is in a once stopped state.

The result of weight measurement of each capsule by the second weighingunit 6 is supplied to the calibration unit (not shown). The calibrationunit compares, for the same capsule, the above result with the result ofweight measurement by the differential transformer type balance 21 ofthe first weighing unit 2; discriminates whether or not the differencetherebetween is within a specific error range; and determines whether ornot the above differential transformer type balance 21 is required to beadjusted or repaired. As a result, in the case where it is determinedthat any one of the differential transformer type balances 21 is notrequired to be adjusted or repaired, the apparatus starts again torepeat the above-described weight selecting operation. On the otherhand, in the case where it is determined that any one of thedifferential transformer type balances 21 is required to be adjusted orrepaired, the apparatus is left as stopped, and informs an operator of awarning sign and also displays on a display unit (not shown) informationindicating which differential transformer type balance 21 is required tobe adjusted or repaired. After the operator adjusts or repairs thedeficient differential transformer type balance 21 on the basis of theinformation, the apparatus starts again to repeat the above-describedweight selecting operation. In this case, by recording the capsuleshaving been processed from the last calibration to the presentcalibration, returning the capsules in the hopper, and re-inspectingthem, it becomes possible to perform highly reliable inspection withouttime-wasting.

Thereafter, the above weight selection is performed with the abovecalibrating operation inserted therein at intervals previouslyarbitrarily set. In this case, the capsule, which has been sampled forcalibration and placed on the pan of the Mettler balance, may be removedfor each calibration. The Mettler balance performs zero point adjustmentfor each calibration even if the capsule remains on the pan, andaccordingly, after the capsules are accumulated somewhat on the pan,they may be removed. In addition, the capsule removed from the pan maybe returned into the hopper 1 and subjected to weight inspection again.

[Embodiment 2]

FIGS. 7 and 8 show a weight selecting apparatus according to a secondembodiment of the present invention, which has a basic configurationsubstantially identical to that of the first embodiment, except that thefeed drum 31 of the apparatus in the first embodiment is replaced with avibration feeder 33 and the non-defective recovering conveyor 44 of theapparatus in the first embodiment is replaced with a non-defectiverecovering drum 46 having four blades as a reversely rotatablenon-defective recovering/carrying device.

In the weight selecting apparatus, as shown in FIG. 7, capsules to beinspected are supplied at random from a hopper 1 into the vibrationfeeder 33 via a belt conveyor 12 and are supplied, through a feed pipe34, into carrying pockets 321 of a carrying roller 32 in uprightpostures on a one-by-one basis by the above-described vibration feeder33; and the capsules ejected from an ejecting chute 41 are ejectedoutside the apparatus through a non-defective recovering chute 441 orrecovered in a temporarily storing vessel 443 through a temporarilystoring chute 442 by rotation of the above-described non-defectiverecovering drum 46.

The vibration feeder 33 will be first described. The vibration feeder 33includes a vibrator 331, and an aligning/feeding plate 332 which ismounted on the vibrator 331 in such a manner as to be tilted a specificangle with respect to the vibrator 331. A plurality of capsule alignmentgrooves 334 in which capsules are to be loosely fitted are formed in anupper surface portion of the aligning/feeding plate 332 along the lengthdirection. A capsule containing portion 333 for containing capsulescharged from the belt conveyor 12 is provided on the upper surface ofthe aligning/feeding plate 332 at one end portion. The number of thecapsule alignment grooves 334 corresponds to the number of rows of thecarrying pockets 321 provided in the carrying roller 32. In thisembodiment, since the carrying roller 32 has 12 rows of the carryingpockets 321 like the first embodiment, the number of the capsulealignment grooves 334 is set at 12 pieces.

A plurality of the feed pipes 34, each being communicated to the leadingend of one of the capsule alignment grooves 334, are connected to theleading end of the aligning/feeding plate 332. The leading end of eachfeed pipe 34 is, as shown in FIG. 7, fixed correspondingly to one of thecarrying pockets 321 of the carrying roller 32 in a state being close tothe outer peripheral surface of the carrying roller 32. In thisembodiment, as shown in FIG. 8, the feed pipe 34 is comprised of aspiral pipe which is formed of a piano wire spirally wound, wherebyvibration of the aligning/feeding plate 332 is absorbed by flexure ofthe spiral pipe.

The feeding of capsules using the vibration feeder 33 is performed asfollows. First, capsules fed at random from the hopper 1 on the beltconveyor 12 are charged in the capsule containing portion 333 of thevibration feeder 33 via the belt conveyor 12, and are fed on thealigning/feeding plate 332 vibrated by vibration generated by thevibrator 331. The capsules fed on the aligning/feeding plate 332 aredropped in the capsule alignment grooves 334 formed in thealigning/feeding plate 332 by vibration of the aligning/feeding plate332, and as shown in FIG. 8, the capsules are aligned along thelongitudinal direction in each of the capsule alignment grooves 334 andare sequentially fed, by vibration, to one of the feed pipes 34 in thestate being aligned in the longitudinal row. The capsules, passingthrough the feed pipe 34, are fed in upright postures one by one intothe carrying pockets 321 of the carrying roller 32 intermittentlyrotated.

Next, the non-defective recovering drum 46 adopted as the non-defectiverecovering/carrying device will be described. The non-defectiverecovering drum 46, having four blades and being rotatable normally andreversely, is disposed between the ejecting chute 41 and a branch pointat which the temporarily storing chute 442 is branched from thenon-defective recovering chute 441.

The non-defective recovering drum 46 is usually rotated counterclockwiseas shown by an arrow in FIG. 7, to feed the capsules flowing in theejecting chute 41 into the non-defective recovering chute 441, therebyejecting the non-defective capsules outside the apparatus. In the casewhere ejection of any defective capsule is not confirmed by a defectiveejection sensor 453 although a defective capsule is detected by anacceptability determining unit (not shown), the non-defective recoveringdrum 46 is reversely rotated clockwise in the figure, to feed thecapsules flowing in the ejecting chute 41 into the temporarily storingchute 442 and recover all of the capsules into the temporarily storingvessel 443 through the temporarily storing chute 442.

It is to be noted that the other configuration, operation, function andeffect are the same as those in the first embodiment, and therefore, thesame parts are indicated by the same reference numerals and theexplanation thereof is omitted.

As described above, according to the weight selecting apparatus in eachof the first and second embodiments, it is possible to perform weightinspection of capsules while automatically performing calibration atspecific intervals previously arbitrarily set, and hence to effectivelyperform highly accurate, highly reliable weight inspection without thenecessity of performing burdensome calibrating operation by manualworks.

In the weight selecting apparatus in each of the first and secondembodiments, since upon calibration, the defective ejecting chute 42,non-defective/defective selecting shutter 43 and defective recoveringconveyor (defective recovering/carrying device) 45, which constitutemain parts of the selecting means 4, constitutes main parts of thesampling means 5, it is possible to certainly perform sampling forcalibration with a relatively simple mechanism by making use of thedefective ejecting path without provision of any complicated path, andhence to miniaturize the apparatus and reduce the parts cost. Further,since the usual weight measurement or inspection cannot be naturallyperformed until the accuracy of each differential transformer balance 21of the first weighing unit 2 is confirmed, the inspection efficiency isnot reduced even by performing sampling for calibration by making use ofthe selecting means 4 as described above.

In the apparatus in each of the first and second embodiments, ejectionof a capsule determined as a defective one by the acceptabilitydetermining unit (not shown) is detected by the defective ejectionsensor 453, and in the case where ejection of any defective capsule isnot detected although a capsule is determined as a defective one by theacceptability determining unit, the non-defective recovering conveyor 44(first embodiment) or the non-defective recovering drum 46 (secondembodiment) is reversely rotated to prevent entrainment of a defectivecapsule in non-defective capsules. This makes it possible to certainlyprevent entrainment of a defective capsule in non-defective capsules,and hence to perform weight measurement with an extremely highreliability.

In the apparatus in each of the first and second embodiments, thecarrying means 3 is comprised of the feed drum 31 (first embodiment) orthe vibration feeder 33 (second embodiment) and the carrying roller 32,wherein each capsule is carried on the pan 24 of the first weighing unit2 by intermittent rotation of the carrying roller 32, and is fed in theejecting chute 41 of the selecting means 4 after weight measurement byintermittent rotation of the carrying roller 32. Accordingly, the numberof parts of the carrying means of the present invention is small ascompared with the carrying means of the above-described related artweight selecting apparatus, and further, the carrying means of thepresent invention does not require any complicated drive mechanism orcontrol mechanism because only the feed drum 31 or vibration feeder 33and carrying roller 32 are taken as movable parts and the motion of eachpart is simple intermittent rotation or vibration.

Consequently, according to the weight selecting apparatus of the presentinvention, as compared with the above-described related art weightselecting apparatus in which objects to be inspected are carried bycontrolling a number of movable parts requiring complicated motions withtimings adjusted accurately, it is possible to accurately, certainlycarry objects to be inspected by a simple mechanism with a reducednumber of parts, and hence to improve the processing ability and reducethe cost.

It is to be noted that the weight selecting apparatus of the presentinvention is not limited to the above-described embodiments but can bemodified in various forms. For example, although in the aboveembodiments the carrying means 3 is comprised of the feed drum 31 (firstembodiment) or vibration feeder 33 (second embodiment) and the carryingroller 32, it may be of any type insofar as it is capable of certainlycarrying capsules to the first weighing unit 2 one by one. Further,although in the above embodiments, capsules for calibration are sampledusing the defective ejecting chute 42, non-defective/defective selectingshutter 43 and defective recovering conveyor (defectiverecovering/carrying device) 45 of the selecting means 4, the samplingmeans may be provided independently from the selecting means 4. Theselecting means 4 is not limited to the configuration using thedefective ejecting chute 42 branched from the ejecting chute 41 and thenon-defective/defective selecting shutter 43, but it may be of any typeinsofar as it is capable of certainly selecting capsules intonon-defective ones and defective ones on the basis of the determinedresult of the acceptability determining unit. The balances used for thefirst weighing unit 2 and the second weighing unit 6 are not limited tothe differential transformer type balance and Mettler balancerespectively but may be other balances or weight measuring instruments.Although in the above embodiments, in the case where the inconvenienceof the first weighing unit 2 is detected by calibration, the operatoradjusts or repairs the first weighing unit 2, the adjustment orrepairing work can be automatically performed using a suitable adjustingmeans or repairing means. The other configurations may be suitablychanged without departing from the scope of the present invention.

As described in the above embodiments, the weight selecting apparatus ofthe present invention is suitable used for weight measurement ofcapsules; however, the objects to be inspected are not limited tocapsules. The weight selecting apparatus of the present invention may besuitably used for weight measurement of various products, for example,other medicines such as tablets, foods, and chemicals, and otherarticles.

According to the present invention, there is provided, as the secondinvention, the weight selecting apparatus characterized in that theintermittently rotatable feed roller having the carrying pockets in theouter peripheral portion are used as the carrying means for carryingobjects to be inspected to the weighing base one by one. In this case,depending on the kind of objects to be inspected or the like, thecalibration function can be omitted. For example, a weight selectingapparatus can be provided in which the members and mechanism associatedwith only calibration are omitted from the weight selecting apparatus ineach of the above embodiments.

As described above, according to the weight selecting apparatus of thepresent invention, it is possible to perform weight inspection ofcapsules while automatically performing calibration at specificintervals previously arbitrarily set, and hence to effectively performhighly accurate, highly reliable weight inspection without the necessityof performing burdensome calibrating operation by manual works.

Further, according to the weight selecting apparatus in which theintermittently rotatable carrying roller having the carrying pockets inthe outer peripheral portion are used as the carrying means, it ispossible to certainly carry objects to be inspected with a relativelysimple mechanism and then perform weight measurement of the objects tobe inspected, and hence to improve the processing ability and reduce thecost such as the parts cost or manufacturing cost.

What is claimed is:
 1. A weight selecting apparatus comprising: a feedunit for continuously feeding objects to be inspected; a first weighingunit for measuring weights of the objects; a carrying means for carryingthe objects fed from said feed unit to said first weighing unit one byone; an acceptability determining unit for comparing the result ofweight measurement by said first weighing unit with a specific referencevalue to determine the acceptability of each of the objects; an ejectingchute for ejecting the objects having been subjected to weightmeasurement by said first weighing unit; a defective ejecting chute,branched from said ejecting chute; a reversely rotatable defectiverecovering/carrying device for carrying the objects fed from saiddefective ejecting chute; a non-defective/defective selecting shutter,provided at the branch point where said defective ejecting chute isbranched from said ejecting chute, for opening/closing a port of saiddefective ejecting chute; a second weighing unit for calibration, whichis adapted to measure weights of sampled objects having been subjectedto weight measurement by said first weighing unit; and a calibrationunit for comparing, for the same object, the result of weightmeasurement by said first weighing unit with the result of weightmeasurement by said second weighing unit and determining whether or nota difference therebetween is within a specific error range; wherein in ausual state, the objects continuously fed from said feed unit arecarried to said first weighing unit one by one by said carrying meansand are subjected to weight measurement by said first weighing unit,being subjected to acceptability determination on the basis of themeasured results by said acceptability determining unit, saidnon-defective/defective selecting shutter is opened/closed on the basisof the determined results, the non-defective objects are ejected throughsaid ejecting chute to be recovered and the defective objects areintroduced from said ejecting chute to said defectiverecovering/carrying device through said defective ejecting chute to berecovered, to thereby select the objects into non-defective ones anddefective ones and recover them; and at specific intervals, saidnon-defective/defective selecting shutter is unconditionally opened tointroduce the objects having being subjected to weight measurement bysaid first weighing unit to said defective recovering/carrying devicethrough said defective ejecting chute, said defectiverecovering/carrying device is reversely rotated to feed the objects tosaid second weighing unit, those of the objects thus fed to said secondweighing unit are subjected to weight measurement by said secondweighing unit; and for the same object, the measured result is comparedwith that obtained by said first weighing unit by means of saidcalibration unit, to perform calibration of said first weighing unit. 2.The weight selecting apparatus according to claim 1, further comprising:a defective ejection sensor for detecting passing of the objects, whichis mounted on said defective ejecting chute or in the vicinity of anejection port thereof; and a reversely rotatable non-defectiverecovering/carrying device for recovering non-defective ones of theobjects, which is disposed ahead of said ejecting chute; whereinejection of the object determined as a defective one by saidacceptability determining unit is detected by said defective ejectionsensor, and in the case where said defective object is not detected,said non-defective recovering/carrying device is reversely rotated toprevent entrainment of said defective object in the non-defectiveobjects.
 3. The weight selecting apparatus according to claim 2, whereinsaid carrying means includes at least one intermittently rotatablecarrying roller having in its outer peripheral surface portion aplurality of carrying pockets for containing the objects, wherein theobjects are contained in said carrying pockets on a one-to-one basis andcarried by intermittent rotation of said carrying roller; each of theobjects is placed on a weighing base of said first weighing unit at thelowermost point of said carrying roller in a state being contained inthe corresponding one of said carrying pockets, being subjected toweight measurement in a period in which the carrying roller is left asintermittently stopped, and is moved from said weighing base byintermittent rotation of said carrying roller; and the object thusmeasured in weight is ejected from said carrying pocket and istransferred to said ejecting chute.
 4. The weight selecting apparatusaccording to claim 1, wherein said carrying means includes at least oneintermittently rotatable carrying roller having in its outer peripheralsurface portion a plurality of carrying pockets for containing theobjects, wherein the objects are contained in said carrying pockets on aone-to-one basis and carried by intermittent rotation of said carryingroller; each of the objects is placed on a weighing base of said firstweighing unit at the lowermost point of said carrying roller in a statebeing contained in the corresponding one of said carrying pockets, beingsubjected to weight measurement in a period in which the carrying rolleris left as intermittently stopped, and is moved from said weighing baseby intermittent rotation of said carrying roller; and the object thusmeasured in weight is ejected from said carrying pocket and istransferred to said ejecting chute.